23 July 2006

A major announcement (hat tip to theWatt.com) came out of the Lucrene Fuel Cell Forum two weeks ago. The president of the conference, Ulf Bossel, presumably with the support of the organizing commity, announced that the pre-eminant European fuel cell conference would no longer be providing a forum for the discussion of hydrogen fuel cells. This is due to the unsuitability of hydrogen as a fuel to power our economy.

Fuel cells are energy converters, not energy sources. They will be part of a sustainable energy solution only if they can compete with other conversion technologies. This includes system parameters, fuels and applications. Time has come for a critical assessment.

...

The European Fuel Cell Forum is committed to the establishment of a safe energy future. Therefore, it will continue to promote fuel cells for sustainable fuels, but discontinue supporting the development of fuel cells for hypothetical fuel supplies. Time has come for decisions. Keeping all options open is not an adequate response to mounting energy problems.

Therefore, the schedule of the European SOFC Forum will be continued in 2008 with an extended conference every second year. Beginning 2007 (July 2 to 6) sustainable energy topics will be emphasized in odd years. Despite earlier announcements the European PEFC Forum series will not be continued.

A series of technical reports on the subject by Ulf Bossel and others is available here. I discussed this on this week's theWatt.com podcast. I would like to reiterate some of the arguments here.

Just to provide a bit of background there are basically two general categories of fuel cells: ones that operate at low temperature − typically below the boiling point of water − and ones that operate at a high temperature of at least several hundred degrees. The proton exchange membrane or PEM fuel cell is the low temperature fuel cell, along with the direct methanol fuel cell. There are many more high temperature fuel cells − examples would be the solid oxide or molten carbonate types. The PEM is unique in that it's the only type that can only burn pure hydrogen; all of the other types can directly burn hydrocarbons of one type or another.

The proponents of the proton exchange membrane fuel cell have promulgated this concept of the 'hydrogen economy' that I'm sure all my readers have seen references too. Basically the hydrogen economy is the idea that we can shift from using fossil fuels to hydrogen as a chemical fuel to power our economy. The transformation would begin with the transportation sector and eventually propagate to providing residential fuel cells that could provide combined heat and power.

There are three major shortcomings of the hydrogen economy concept:

Production.

Storage.

Distribution.

Distribution is basically a chicken and egg problem. No one wants to buy a hydrogen car until there are fueling stations available and no corporation wants to invest in hydrogen fueling stations until there are customers on the road. Building the hydrogen economy would require an absolutely massive capital investment. For example, none of our current natural gas pipelines are capable of handling hydrogen because it’s a highly corrosive substance.

The storage problem is partly technological and partly the laws of physics. The basic difficulty comes from the fact that hydrogen has an extremely low density: liquid hydrogen a density of only 80 k/m3. In order to get hydrogen from a lighter than air gas to some usable stored form it needs to be compressed, liquefied, or chemically bonded. All of these means need to consume a large fraction of the energy of the hydrogen to get it to that state. Hydrogen is not like gasoline. You cannot pull up to a station and pump your tank full in a couple of minutes. A lot of people don't realize that pumping up a high-pressure compressed hydrogen tank can easily take 30 - 60 minutes.

The last problem is that of production; it is the most fundamental problem and it’s the basis of the schism that's occurred at the Lucerne Fuel Cell Forum. Unlike fossil fuels hydrogen doesn't exist in nature on Earth − we can't poke a hole in the ground and pump out hydrogen formed from long-dead plants. Hydrogen isn't an energy source; it's an energy currency, like electricity. Elemental hydrogen has to be produced from other compounds such as water or hydrocarbons.

When it comes to producing hydrogen from fossil fuels the high temperature fuel cell guys rightly get out their signing voice and break into their best rendition of, "Anything you can do I can do better..." from Mary Poppins. The solid oxide fuel cell and other types can all burn natural gas, gasified coal and biomass at a higher efficiency than converting those feedstocks to hydrogen and using a PEM cell.

That leaves producing hydrogen from the electrolysis of water, which is the supposedly ‘green’ option. The reality is that the electrolysis to fuel cell path is a terribly inefficient method to convert solar, wind, and nuclear energy to useful work. Let us consider the production of hydrogen from wind power. First you have to rectify the alternating current to direct current to power the electrolyzer, which is about 90 % efficient. An electrolyzer is optimistically 75 % efficient so you lose another quarter of your energy there. Then you need to store the hydrogen, by say compressing it under high pressure. This would consume about 20 % of the energy content of the hydrogen, and distributing it perhaps another 10 %. Now we finally have the hydrogen at the fuel cell but then we have to remember that the fuel cell is maybe 50 % efficient. The product of the fuel cell is direct current electricity, so in the end we’ve gone through a whole bunch of steps in a big circle. When you multiply all these factors together you find that the well-to-wheel (or source-to-sink) efficiency is only about 25 %.

The obvious question that Ulf Bossel and people such as myself ask is why go to all that trouble? Why not just transmit and use the electricity directly? High-voltage direct current electricity transmission is just as efficient as pipelining hydrogen. If we allow for 90 % efficiency for rectifying and 90 % for transmission we end up with 3.3 times more energy for the electricity economy than the hydrogen economy. If you want to include batteries the math doesn’t change much because the round-trip efficiency of batteries is really very high – 90 % for lithium-ion batteries. As Bossel states, hydrogen cannot compete with its own fuel source − in this case, electrons. This poor efficiency of the hydrogen economy that I’ve talked about is not something that has a solution through improved technology. The laws of thermodynamics maintain the limiting factor here. All the extra steps in the hydrogen case produce entropy, and there’s no way to get past certain theoretical limits to the efficiency of each stage.

The inefficiency of hydrogen isn’t something that we can afford environmentally. Would anyone consider it better to have three wind turbines rather than one, or three nuclear power plants rather than one? If you try to figure out how many power plants we would need to implement the hydrogen economy it becomes readily apparent what a fantasyland it is. The USA uses approximately 20 million barrels of oil per day. If we were to replace every gallon of gasoline with a kilogram of hydrogen we would require 1.4 TW of continuous power. However, there’s only 0.9 TW currently installed, of which about 2/3rds is used on average, so the idea of trying to use nighttime power to produce hydrogen won’t work. The existing infrastructure is incapable of powering a hydrogen economy – we’re talking about 1500 large nuclear power plants. So not only would we have to change our entire distribution network but we would also have to massively ramp up electricity production. The expense of the whole idea is terrifying.

This is sharply contrasted with trying to develop plug-in vehicles, electrified rail and such. Because the electricity path is so much more efficient we can actually dump almost all of our transportation energy needs on the existing electricity grid. If we throw in some efficiency improvements to the residential and commercial sectors then everything is peachy. The existing electrical grid that we have may not seem as sexy as hydrogen but it’s definitely the better option.

What's happened at Lucrene is that the rest of the fuel cell community have gotten tired of the empty promises of the hydrogen economy and are fighting back. PEM fuel cells have been receiving a disproportionate share of funding into all alternate energy technologies. What Ulf Bossel is saying is that is we have to refocus our efforts and monies onto technologies that we know will actually work rather than some idea put forth by a special interest group. Of course, the PEM researchers don’t want to hear this. Careers are at stake so I wouldn’t expect abandonment of the hydrogen economy concept quite yet.

10 July 2006

Billmon, one of the more amusing bloggers out here, recently wrote an acerbic rendition of Al Gore's quest to moderate global warming. However, the bulk of his post is not about global warming per say but rather a grouchy old man railing about how thick-headed the people of this world are. While the gist of his argument is true, it is also not novel. If you went to Victorian times and took a survey of intellectual blowhards of that period, I am sure that they would feel that an even largely segment of the population is composed of blockheads then we would currently. This is not to say that we should be satisfied with the way our education system currently works. Clearly it doesn't go fair enough in training the minds of young pupils. Spoon-feeding facts into someone's brain isn't useful if you lack the capacity to properly utilize them.

Many people lack the ability to differentiate science from pseudo-science and moreover could not even suggest how one might go about doing so. When I write a post about wind or biofuels and then follow it up a couple of days later with another discussion that pans my original talking points it is not because I lack "strength of conviction" or some other absurd form of weakness. I challenge myself because I am fully aware of the fallibility of my assumptions and the need to constantly assess my position to ensure that it is quantitatively factually correct.

The only way to enlighten people is to slowly chip away at their preconceptions of the world. The idea of critical thinking as a standard practice needs to insidiously infiltrate the manner in which people think. This is especially important in the world of energy and the environment which are now so interwoven to form a Gordian knot. To me, when an environmental group such as Greenpeace boils down their energy policy to solar and wind, it is just as intellectually dishonest as CEI's "Carbon Dioxide is Life" campaign. Both policies can be easily demonstrated to be bogus.

I would like to discus some of the basics of scientific thinking. This is adapted from a small book, "Miniature Guide on Scientific Thinking," by the Foundation for Critical Thinking. Unfortunately this doesn't appear to be available on their website any longer.

Development of the Scientific Mind

Unscientific thinker: Unaware of significant problems in thinking about scientific issues. Hence one is unable to distinguish science from pseudo-science.

Challenged thinker: Beings to recognize that one often fails to think scientifically when considering scientific questions.

Accomplished Scientific Thinker: Good habits of scientific thought have become second nature.

Obviously one needs to advance, step-by-painful-step from one stage to the next. As the text puts it:

Scientific thinkers routinely apply intellectual standards to the elements of scientific reasoning as they develop the traits of a scientific mind.

So what are these standards, and how do lead us to scientific thinking?

Essential Intellectual Standards

Clarity

Precision

Accuracy

Bias

Correlation

Completeness

Logic

Consistency

Soundness

Relevance

|
must be applied to
↓

Elements of Scientific Thought

Definition

Hypothesis

Conceptualization

Assumptions

Causation

Testability

Inference

Implication

Points of View

Conclusion

Sources of Error

Skepticism

|
to develop
↓

Traits of a Scientific Mind

Humility

Perseverance

Autonomy

Confidence in Reason

Integrity

Intellectual Empathy

Intellectual Courage

Fairmindedness

Wikipedia is not a bad place to start if you don't understand the difference between precision and accuracy, correlation and causation, or inference and implication. If you would like some less escapist summer reading, and would like to start the process of training your mind, Carl "Billions and billions" Sagan's book "The Demon Haunted World: Science as a Candle in the Dark" is a good place to start. Better yet, give it to a friend once you've read it. For a more humourous look at the world from a skeptic's perspective, Bob Park's What's New is a weekly snarky look at events in the USA that are relevant to the world of science.

Load-following power: Hydroelectric or natural gas turbines that can rapidly shift their output to meet demand or compensate for fluctuations in renewable supply.

I've been meaning to write a post that details a hypothetical future power mix where a large proportion of electricity is generated by renewable sources. For whatever reason, I've now finally gotten around to it. The objective of this post is to take some demand data, generate some supply data for renewables, and mix it all together in order to get a grasp of what the general case might be.

I picked Texas as a source of electricity demand data simply because the information is published on the web. I used the data for June 15th, 2006 but then scaled it up so that the maximum demand for the day was 100 000 MW.

I then tried to meet this demand with 35 000 MW of nuclear power, 120 000 MW of wind power, 75 000 MW of solar power, and 65 000 MW of hydroelectric power. The wind data is simulated but the solar data is real, for San Antonio in 2003. In order to try to smooth the data to reflect geographic distribution of wind and solar farms I averaged the daily wind speeds and insolation for five days spread over a total of five months. I think it is a reasonable approximation to use temporal averaging to imitate geographical averaging. In spite of averaging the data over such a long period there's still a considerable bottoming out in the wind power production at 5:00 am. This is an irritating part of the nature of wind: it is unreliable and hence must be backed by spare capacity from other sources.

Once the nuclear, wind, and solar power production was all accounted for I used hydroelectric power to fill in the gap (when it existed) between supply and demand. The objective is to preserve the water in the reservoir (or natural gas supplies) whenever possible. This allows us, essentially, to trade some of the inherent power quality of hydroelectric to the low power quality renewable sources.

The results are fairly intuitive. Base-load power provides the solid bottom portion of the power mix. Wind is chaotic. Solar correlates mildly with the daily peak in demand, but not as well as we might want. The correlation could actually be fooled with by adjusting time zones.

Table 1: Daily Power Demand

Total Daily Power Demand

2 262 622 MWh

Maximum Power Demand

100 000 MW

Minimum Power Demand

87 038 MW

Excess Production

60 853 MWh

There is some excess power produced during the day, although it is a relatively small proportion of the total (2.3 %). This is a result of the unpredictable nature of wind as much as anything else. While solar can be forecast relatively well, wind cannot.

Table 2: Daily Power Generation

Source

Total Generation

(MWh)

Peak Generation

(MW)

Rated

Capacity

(MW)

Production Share(%)

Model Capacity Factor

TypicalCapacityFactor

Nuclear

840 000

35 000

35 000

36.1

1.0

0.7 - 0.9

Wind

605 860

41 509

120 000

26.1

0.21

0.2 - 0.3

Solar

337 515

48 300

75 000

14.5

0.19

0.15 - 0.25

Hydro

540 099

45 966

65 000

23.2

0.34

0.0 - 1.0

There are certainly a number of notable facts to take from this little simulation in a day in the life of Texas electrons. One is that the need for scalable power is quite high (~ 25 %). For a nation like the USA, which is poor in hydroelectric power, it implies that they will continue to need to burn large quantities of natural gas for electricity in the future. The other is that with the widespread deployment of renewables you are almost guaranteed to produce more power than you can use on a common basis. It would be very nice to incorporate power storage solutions like pumped hydro or flow batteries into the grid to utilize this excess power but my past work generally indicates that stationary arbitrage systems have poor margins. The next step past storage is deferrable demand, generally in the form of plug-in hybrid or electric vehicles. A plug-in hybrid does not need to be fully charged from the moment it is plugged into the grid because it has a backup chemical fuel supply. Instead it can wait and accept energy only when the grid is saturated and presumably get a cheaper rate for its trouble. In the case of a plug-in hybrid, the battery is purchased not for the primary purpose of conducting arbitrage but instead providing power for a vehicle. In a sense, the secondary benefit to the electricity grid would be subsidized by personal transportation.

02 July 2006

A comment Nick made about interest on the capital costs of a photovoltaic power plant got me thinking: maybe one of the reasons that wind and solar power are experiencing such explosive growth is their small incremental capital cost. Wind turbines typically come with a power rating of 1000 - 300 kW while photovoltaic systems can be built in any practical increment. On the other hand, a nuclear power plant, a hydroelectric dam, or any other centralized power plant can only be built in extremely large increments (300+ MW). The capital cost for a nuclear or coal power plant is three or four orders of magnitude higher than that of a wind turbine. Because of this, a wind power investment can grow much closer to the exponential curve than big thermal power plants.

The financial advantage essentially works like this: assume that you have a nuclear plant and a wind farm and that both systems have the same rate of return. For my case study, I will assume that the system's net revenue is 20 % of its capital cost every year. Nominally you could build a new centralized power plant every five years if you reinvested all of your profits. Consider instead a wind farm that produced the same average power (with the same capital cost per Megawatt). If each turbine cost 1/1000th that of a major nuclear plant then a new one could be purchased every two days. As it will become apparent, the law of compound interest greatly favours the source that can be built in smaller increments.

In order to test this theory I constructed a model to compare the growth of an abstract wind farm and nuclear plant investment. Both the nuclear and wind farm investor took a loan sufficient to build 1000 MW of capacity. This is assumed to be average capacity, with the capacity factor of each already included. I will also incorporate a 2 % interest rate − indexed to inflation − on all cash balances held (positive or negative). The last thing I would like to model is a delay between the allocation of funds and the power plant actually coming on-line. For the 'nuclear' the delay is two years to account for construction, for 'wind' the delay is thirty days.

The interest rate is quite small compared to the profit on the plants so it should take approximately five years for the nuclear plant to payoff the loan, another five years to accumulate enough capital to pay for a new one, and two more years to actually build the plant. That's twelve years before the second nuclear plant can be constructed. For wind, it will take the same five years to payoff the loan but then it will only take two days to earn enough money to build another turbine and then thirty days for the turbine to be installed. One can guess that this is not going to turn out well for the nuclear option but nothing illustrates this better than a figure.

After twenty years the wind farm will already have outgrown the nuclear capacity by a factor of 17850 MW to 5000 MW. The wind-based power system will provide 3.6x more power than the nuclear based system. This doesn't let wind power off the hook with regard to its intermittent nature but it certainly goes a long way to explain why solar and wind are seeing such explosive growth around the world. One could certainly play with my model to include other factors, change the rate of return or interest rates. However, the big picture isn't going to change unless the large capital investment power installations can massively outperform solar and wind with regards to the rate of return.

The growth rate advantage is not the whole story, of course. It is much easier to secure a few million in financing than a few billion. Similarly, the incremental risk of putting up a new wind turbine is quite low. The risk is also reduced by the fact that there are no fluctuating fuel costs associated with renewables versus fossil or nuclear fuels.

01 July 2006

For my Canada Day post, I'd like to say that Canada is not doing well at all on the greenhouse gas emissions front.

The Conservative Prime Minister Steven Harper and his Minister of Environment, Rhonda Ambrose, have taken a lot of heat for abrogating the Kyoto treaty on climate change. My feelings on this have been ambivalent. While I hardly think the Conservatives are going to govern in a pro-environment fashion, at least they are being honest with the population. In a parliamentary system when the governing party passes legislation, everyone knows who wrote it and who passed it. There's none of the bizarre amendments that are so omnipresent in the US Congress and you can't run away from your record very easily. In comparison, all the Liberal party was doing was offering empty platitudes to the green vote. I mean really, can anyone name a successful program instituted by the Liberal party that helped reduce greenhouse gas emissions? The "One Tonne Challenge"? Please... Liberals pander to environmentalists in order to get their votes, but in office they don't actually effect any significant policy changes. Canada has a resource-based economy, and on our current course we could actually manage to pass the USA in per capita greenhouse gas emissions in spite of our relatively green electricity production infrastructure.

Also much of the criticism against Kyoto is strong. I certainly can't see the value of shipping money to Eastern Europe (whose economies and hence emissions collapsed in the 1990s) in order to 'offset' CO2 emission. It would be far better to spend that money nationally on programs to actually reduce greenhouse gas emissions. The fact is, as soon as the Bush administration decided not to ratify Kyoto, the treaty was dead. The American influence on the global economy and global environment is far too massive to be sidestepped. The fact that coal-powered China also has no incentive to take another path (aside from destroying their local environment) is another nail in the coffin.

The sad fact of the matter is that Canada could probably meet its Kyoto targets without a lot of fuss:

Eliminate raw methane emissions. Methane has 22 x the global warming potential as CO2 so the benefit on a mole by mole basis is very big. Methane mainly comes from two sources: the oil and gas industry and waste streams (landfills and wastewater). For the oil and gas industry, the government would need to institute regulations to vastly reduce the amount of methane that is permitted to leak out of natural gas pipelines and wellheads. Reducing methane production from wastewater (sewage) and landfills is a matter [edit] of caping them and introducing anaerobic bacteria to eat the carbohydrates and cellulose in order to produce biogas, a mixture of methane and carbon dioxide. Biogas is typically burned in large diesel engines to provide electricity; in the future solid oxide fuel cells could be used. [/edit]

Introduce a feebate program on cars and light trucks without any loopholes. Canadian fleet fuel economy is pathetic. More long term programs to improve the transportation sector would include pushing freight onto electrified rail and improving the quantity and quality of public transit. I've lived in both Victoria and Edmonton and in both busses are generally filled to overcapacity during rush hour. Canada in itself is not big enough to induce new technologies like the plug-in hybrid to appear on the marketplace but we can still make a huge impact by slowing shifting the structural framework of the transportation sector to use sustainable energy and be more efficient.

Further green the electricity sector so that we can better make the argument that switching to electricity is the way to go. Investing in a more robust electrical grid with more DC connections will payoff in any future. 57 % of our electricity comes from hydro and 13 % from nuclear. The obvious missing factor is wind. While Alberta has some significant wind development (and amazing katabatic winds coming off the Rocky Mountains) Canada in general lags behind every developed nation in wind. The hydro provinces (Quebec, British Columbia, and Manitoba) are uniquely well suited to use their reservoirs to handle the intermittency problems of wind power. Alberta and Saskatchewan should be pushing carbon dioxide sequesterization much harder. I live in Edmonton so I understand that it would be practically impossible to convince the province to get off coal but pumping CO2 underground has a real potential economic value for tertiary recovery of conventional oil and gas. The experience at Weyburn has been positive and the government could be pushing this technology far, far harder. Ontario doesn't have the thick sedimentary basin of the prairie provinces so they appear to be stuck with nuclear power for the moment. (Oh, and which is more environmentally benign, new nuclear plants in Ontario or new hydro-electric dams in Quebec?)

Continue to increase EnerGuide standards on appliances and offer programs to encourage residential and commercial building owners to retrofit their structures to use less electricity and natural gas. Consider for example how grossly excessive the lighting in most commercial buildings is. The bathrooms in new buildings on the University of Alberta campus usually have motion sensors that turn on when you enter. This sort of technology should see more common use. Putting photosensors on hall lighting to turn the lights off when the sun is shining from the outside would be another positive step to reduce wasted electricity.

A pretty simple and achievable plan in my opinion: push hard on methane, increase car fuel economy standards and push public transit and rail, invest in green electricity generation, push efficiency and conservation through government standards. None of these policies would have a significant harmful impact on the economy and in the long-run, improving energy efficiency will benefit any country.

I've been long fed-up with the collection of plastic shopping bags I accumulate from grocery shopping only to have them 'recycled' in some Chinese incinerator. This is not to mention the lovely elongation behavior of low-density polyethylene when you've got a 4L jug of milk in one bag. For some reason I don’t like cutting off the circulation to my fingers whenever I go out to buy milk.

Unfortunately, the vast majority of reusable shopping bags seem to be made out of some sissified natural fibre with some smarmy hippy logo on the side. Edmonton, being a city of pimped-up pickup trucks that have never had a load in the bed, let alone been off-road, doesn't always appreciate hemp bags with a cannabis label on the side.

What I want is a basic rugged, square-bottom bag with wide handles. So do any of my readers have any recommendations (assuming I still have any -- I hope you're all RSS subscribers...)?

On a different tack, CBC has been running a 'reality' television series called Code Green. Homeowners are given $15,000 to renovate their residence in order to reduce the amount of electricity, water, and heat that they consume. After the renovations are complete the homes are monitored for a month to determine how well they have done. Each installation then competes against other families to see who can reduce their carbon footprint the most, with the top team winning a Toyota Prius.

A colleague of mine were discussing how screwed up this competition would be if you tried to run it for apartment renters rather than homeowners. Take my case: I don't pay for heat or hot water, just electricity. However, the largest source of electricity consumption in my apartment is the refrigerator, an appliance that is the responsibility of my landlord. As such we have this messed up benefits for conservation. If I reduce my hot water consumption, my landlord saves money. If my landlord replaces my fridge, I save money. The problem is obvious. I can open the window in the winter to let in fresh air and totally ignore the extra natural gas burning the building's boiler. My colleague doesn't even pay for power.

This is an obvious area in which government regulation on the way this consumption is paid for would be beneficial. My coin-operated laundry costs $1.75 for washing and $1.25 for drying. I pay the same price for washing in hot or cold water. Ben@theWatt.com has already noted that apartment washers are basically a big cash cow for apartment owners but wouldn't it be nice to have a slightly smarter system where I could pay less for washing with cold water rather than warm or hot?